LPWAN tutorial-LPWAN features, LPWAN architecture, LPWAN benefits

This LPWAN tutorial covers LPWAN network basics,LPWAN architecture and LPWAN benefits. LPWAN systems include LoRa, Sigfox, EC-GSM, NB-IoT, LTE-M, DASH7, Weightless, NB-Fi etc.

What is LPWAN ?

LPWAN is a type of wireless network used for low power, long range and low bandwidth applications. These requirements are typically found in IoT and M2M scenarios. LPWAN is used for various applications viz. smart tracking, smart grid, smart parking, smart city, smart agriculture and so on. The figure-1 depicst LPWAN standards.

The figure-2 depicts LPWAN comparison with other wireless technologies with respect to various system parameters viz. bandwidth, latency, range, power consumption, coverage penetration, costs and number of BSs. It operates on sub GHz frequency band.

Advantages of LPWAN,Disadvantages of LPWAN

As shown LPWAN supports longer range, low power consumption, deeper penetration and wide coverage. It supports longer transmission latency which is not primary requirement of LPWAN. Let us understand features or characteristics of LPWAN.

LPWAN features or characteristics

Following are the features or characteristics of LPWAN network.
• It offers long range approx. in 5 to 40 Km in open field region.
• It consumes ultra low power which extends battery lifetime of about 10 years.
• It offers throughput of few hundred bps or less.
• Radio chipset costs $2 or less.
• Number of base stations required is less and single BS can serve thousands of LPWAN devices or sensors.
• It offers excellent coverage with good in-building and in-ground penetration.

LPWAN architecture

The figure depicts LPWAN network architecture. As shown in the architecture, LPWAN system consists of LPWAN end devices, Base Stations, Gateways, Access network/Internet and cloud servers. The LPWAN network uses star topology as it avoids complex routing algorithms required in mesh topology. This simplifies the implementation and reduces power consumption to greater extent compare to mesh.

End Devices:
There are two types of devices which make use of LPWAN network. Long range devices (based on LoRa, NB-Fi) directly connect with Base station. Short range devices (based on Zigbee or Bluetooth) connect with Base Station via LPWAN gateway.

Base Station (BS):
It connects one side with end devices or gateways and the other side with Access Network or internet service provider. Single BS can handle large number of devices. TCP/IP is used to transport traffic between BS and cloud servers. BS handles protocol translation between IoT protocols and application protocols. MQTT and CoAP are common protocol found in IoT applications.

LPWAN Gateway:
The Gateway is used to provide network connectivity for short range devices based on BLE and Zigbee standards. It often takes care of conversion between LPWAN and Short Range Device based radio technologies as well as their respective protocols. Gateway usually runs on mains power supply as it has to handle large end devices. Gateway is also equipped with encryption algorithms to support end to end security.

Cloud server and apps:
The cloud storage refers to the service in which user data is remotely maintained, managed as well as backed up or stored. The service is usually available to the users over internet. In this concept, user will store the files online using internet to the external servers maintained by the cloud storage service providers. The cloud storage delivery models are of four types viz. Public Cloud, Private Cloud, Hybrid Cloud and Community Cloud. Refer cloud storage tutorial and cloud computing tutorial for understanding cloud infrastructure and more.

LPWAN Benefits

Following are the benefits of LPWAN.
➨Longer range
➨Long device life cycle
➨Low cost of gateways/BSs/Sensors
➨Lower requirement of BSs
➨The sub GHz frequency band used in LPWAN helps system operate under complex channel conditions.
➨Deeper penetration through walls and building basements.
➨Simple network installation, easy network management
➨It offers secured data communication between nodes and Gateways due to use of encryption algorithms.